The identification and implementation of appropriate services for homeless adults with serious alcohol problems constitute prominent health, social, and political issues. Despite fairly reliable information on the high prevalence of alcohol problems among homeless adults, virtually no data are available on the dynamics of homelessness and its relationship to alcohol problems. Furthermore, little is known about how contact with treatment programs or contact with other services might influence the course of homelessness. This study submits 1991 longitudinal survey data on a probability sample of 564 homeless adults in Alameda County, California to analysis. The project investigates (1) the prevalence and distribution of alcohol problems and service utilization patterns, including contact with alcohol treatment and other service systems among homeless adults; (2) the relationship between alcohol use and homelessness among adults; (3) the mediating effect of alcohol treatment utilization on the course of homelessness; and (4) the degree to which problem drinkers among the homeless population are served by alcohol treatment programs. Evaluation of service utilization and its connection to homeless careers and alcohol consumption patterns will prove central to the effort to craft proper networks and service systems. Findings will be of use to refine and focus scarce resources to serve homeless individuals with alcohol problems.